Please help

[Feldenak]

Troubleshooting starter

1. Overview of the problem
   Stuck in start-up sequence without reaching POST.
   
   
2. Full description of the problem and symptoms
   Building a new machine. No POST. I've tried new mobo, CPU, and PSU all with the same results. When I hit the power button, the fans will spin up and mobo LEDs fire up. It stays on for about 1-2 seconds the shuts down and starts back on it's own and stays in that cycle until I turn the PSU off. I've pulled the mobo out of the case and tried starting it on a piece of cardboard and the same symptoms persist. The only thing that seems to keep it "on" is pulling the 4-pin ATX power cord from the mobo, but then the CPU isn't getting power. Only thing on the mobo is CPU and HSF, all other expansion cards are off the board.
   
   Edit: I've also eliminated the case power button as an issue. I've used a screwdriver to make the connection on the mobo.
   
3. Did it work normally at one time, or has the problem always existed?
   Brand new build, never POSTed.
   
   
   
4. Is the problem consistent and repeatable, or entirely random, or semi-random?
   Apparently it's repeatable. Pulling the 4-pin ATX power cord from the mobo seems to keep the fans running and the cycle doesn't happen.
   
   
   
5. I already tried these steps:
   Swapped, CPU, mobo and PSU and still getting same results. Also tried firing things up outside the case in the thought that maybe something was shorting out in the case...same loop.
   
   
   
   
6. My hardware
   • System brand & model, if it?s a pre-built system such as a Dell, HP, Gateway, etc. If it?s not, fill in as much of the information below as you can.
     
   • Motherboard brand & model: Gigabyte GA-EP45-DS3L
   • CPU model (and is it overclocked?): Core 2 Duo E8400 (stock cooling)
   • Video card(s) brand & model: Not plugged into the mobo b/c of troubleshooting but it's a Asus HD 4870 1GB
   • RAM modules brand & model: RAM not currently on the mobo b/c of troubleshooting but it's Mushkin 240-Pin DDR2 800
   • Power supply brand & model: Tried both OCZ OCZ600MXSP and Antec EA650
   
   

 

[Atheus]

Well if you swapped all three of CPU, mobo, PSU, then you have a whole new computer don't you. It should have worked.

The only think I can think of is you replaced the CPU and/or motherboard before replacing the PSU and it blew the new parts.

 

[earthman]

What happens when you try to post with video and memory?

 

[Elias824]

Bad ram maybe, or its defaulted to a bad setting. One thing you can try is clearing the bios, sometimes that helps.

 

[TheKub]

Originally posted by: Feldenak
[*]Video card(s) brand & model: Not plugged into the mobo b/c of troubleshooting but it's a Asus HD 4870 1GB
[*]RAM modules brand & model: RAM not currently on the mobo b/c of troubleshooting but it's Mushkin 240-Pin DDR2 800

?? Im assuming you put these in during your tests becase a system WILL NOT POST without vid\mem.

 

[Feldenak]

Originally posted by: TheKub

Originally posted by: Feldenak
[*]Video card(s) brand & model: Not plugged into the mobo b/c of troubleshooting but it's a Asus HD 4870 1GB
[*]RAM modules brand & model: RAM not currently on the mobo b/c of troubleshooting but it's Mushkin 240-Pin DDR2 800

?? Im assuming you put these in during your tests becase a system WILL NOT POST without vid\mem.

I took them out as part of my testing to see if the computer would stay on and stop cycling up and down.

I'm not sure what the problem was but it seems to be working flawlessly now. Basically, I took everything out of the case and started over. I wish I could add something to the collective knowledge here about the issue but I have no idea what was causing it nor what exactly fixed the problem.

 

[Frankdaatank24]

Something might have been grounding out a component on the motherboard, a stray screw, metal shavings from the case, something.

 

[earthman]

You can't post a system without video or memory, how would you even know what's happening?

 

[Ausm]

This may sound stupid but I ran into this a while back and found out that it was a faulty surge protector that I was using was causing the problem. It seems VERY unlikely that you would get the same results even when you virtually swapped out every piece of hardware in there.

 

[Blazer]

whatever the problem was you still need to run a stress test on the system, prime95 or such, memtest or OCA from Microsoft, stress test for the video card.

there hard to find but a good brand name single 12v rail power supply with at least 24 amps on the 12v rail.